1997 GMC Yukon - Answered Questions & Fixed issues

Check the transmission fluid level with the vehicle idling in park. If you do not see fluid on the dipstick then add one half quart at a time until it is in the hash marks on the dip stick. be sure to let the transmission (DexIII or mercon) completely drain down the dipstick tube or you will get a false reading. Shut off engine to avoid having to warm up the transmission to get an accurate reading and possibly causing (more) damage then may already have been done.

I would need to look at this. but one thing are the hoses new?

That's often a sign of a failing check valve in the fuel pump. Try this. When you turn the key to RUN, the fuel pump activates for 2-seconds to boost any lost pressure. Try turning the key to RUN, then OFF and repeat three times. If the engine starts right up, you probably need a new fuel pump. The real test is called a leakdown test where the shop throws a pressure gauge on it and leaves it overnight. If it loses more than 5-10-psi, the check valve is shot. Can't be replaced separately .

Make sure that the starter solenoid is being activated and getting power to the starter. All battery connections and starter motor connection must be squeaky clean since any resistance in a 12 volt system may have a serious impact on power flow to device. Ignore the radio, heater etc during startup - the car is designed to turn them off when you turn the key to start so all power goes to the starter motor only.

There is a problem with the torque converter or transmission. Sometimes cleaning out the transmission with new fluid and filter will solve such issues, but no such luck this time. Take it to a reputable transmission repair shop for an estimate. In the meantime, shift to "N" when you must apply the brakes, then shift to "D" when you want to go again. You may be able to save money by removing the transmission yourself and taking it to the shop, but let them see the vehicle first to confirm the diagnosis. On front-wheel drive cars, pulling the transmission is a major job; you will probably need to hoist the engine and transmission out together, or disassemble most of the front suspension.

Your best bet take it to a qualified repair shop that can do the diagnostics for the codes, no code tells you to replace a sensor . Viewing scan data on a professional scan tool an doing diagnostics CatalystSystem Efficiency Below Threshold(bank2) ! This means you need to have a catalytic converter replaced . 080 EGR and Catalytic Converter Tests EGR Test

Power Door Locks Circuit Description The power door lock system incorporates door lock switches on both front doors and on the RH D-pillar, door lock motors in all passenger doors and in the RR cargo door, a door lock relay and a door lock control module. Power for the door lock switches and the door lock control module is supplied from the CIG LTR fuse 13 through CKT 640 (ORN). Power for the door lock relay is supplied from the PWR ACCY circuit breaker through CKT 540 (ORN). Ground for the door lock relay is supplied from G202 through CKT 150 (BLK) and ground for the door lock control module is supplied from G400 through CKT 150 (BLK). The door lock motors are reversible and both sides are connected to the normally closed contacts of the door lock relay. Those contacts of the relay are connected to G202. When any of the door lock switches are placed in the lock position, voltage is supplied through CKT 195 (LT BLU) to the relay lock coil. Since the other side of the lock coil is connected to ground, the coil is energized and it pulls the lock contacts closed. Voltage is then supplied through CKT 295 (GRY) to all the door lock motors and the doors lock. The unlock function operates in much the same manner except that when any of the switches are placed in the unlock position, voltage is supplied through CKT 194 (WHT) to the unlock coil of the relay and CKT 294 (TAN) supplies voltage to the apposite side of the door lock motor and the doors unlock. Door Lock Control Module Description The door lock control module is used on vehicles equipped with cargo doors. The purpose of the module is to lock the cargo doors after a lock cycle has been commanded from any of the door lock switches with the cargo doors open. When the RH cargo door is open, the module receives a ground signal from the closed contacts of the rear door jamb switch on CKT 1897 (ORN/BLK) to G400. When a lock command is received, the module retains this input until it receives an open input from the rear door jamb switch. Then the module sends a lock command through CKT 194 (WHT) to the door lock relay and the doors lock. Rear Cargo Doors Description The power door lock motor will not operate unless the rear cargo doors are fully closed. The power door lock motor is in the right cargo door. The contactors are on the rear cargo door opening on the body and on the right cargo door.

Your Yukon has only one O2 sensor. If black smoke is present at exhaust pipe while at hi-way speed, it is probably staying in open loop (fuel mapping). most likely a coolant temp sensor. Before changing any parts, perform an OBDII diagnostic test to see the stored fault history. Replace cheapest components first (ie air filter, every 40,000 miles)

I would also suspect the ignition module. They tend to work ok for a few minutes when they are cold, then fail once they warm up. If you wait awhile for the ICM to cool down, it will work as well as it can until it warms up again. A code scanner is your best friend to know where to start looking, and to perform tests and log data.

Step by Step Troubleshooting 4wd 4x4 88-98 Chevy GMC ...

? 21:32 https://www.youtube.com/watch?v=Su9Dkrfd_Zg Jan 20, 2014 - Uploaded by rwdelling Step by Step Troubleshooting 4wd 4x4 88-98 Chevy GMC Truck ... flashing indicator lights and then would not shift from 2-4wd atall. .... 1997 2dr Tahoe in Nov and I've been having the same problems all winter. I was getting worried thinking I would have to pay a lot of money to get my 4WD working again.

You need a scan tool to retrieve the diagnostic trouble codes and repair the fault and clear the code.

Most fuel injected vehicles no longer experience vapor lock, since fuel circulates continuously thru the fuel rail and back to the tank. More likely, you have an electrical part which gets hot once you shut the truck off. You need to test for spark to the plugs, and also correct fuel pressure when it fails to start and see which is lacking.

here is a video on where it is and how to install it :)

If not On the starter
Then the fuse box under the hood
Should be the location of the alternater fuse

Usually if the cable is bad enough to click, the speedo will jump a little with each click. Get passenger to lie on floor with section of rubber hose. Stick one end in ear and poke other end around under dash to try to locate sound.

when you say it wont start will the engine turn over?
if it wont turn over i think you should check your battery connections
if the engine turns over then you need to check your fuel pressure and spark and let me lknow

The object on top of the intake is the throttle body. Are you getting power to the injectors, and a ground signal from the engine computer ? ?

This could be a few things. Ignition wires that have become worn or broken. A distrubuter cap and or rotor that is worn. OR. in the intake the fiuel delivery system aka the spider is leaking at one or more places. This is common as is the above. Check your fuel filter too however though the free should be checked it is not likely the cause in this case.

Transmission shop. Let them run a diagnostic on it.

DTC P0157 HO2S Circuit Low Voltage Bank 2 Sensor 2 Check for the following: HO2S wire - Sensor pigtail may be mispositioned and contacting the exhaust manifold Intermittent ground in the wire between the connector and the sensor Poor VCM to engine block ground Lean injector(s). Perform Fuel Injector Balance Test for the 5.7L or the 7.4L. Fuel contamination. Water, even in small amounts, near the in-tank fuel pump inlet can be delivered to the injectors. The water causes a lean exhaust and can set a DTC P0151 Fuel pressure. System will be lean if pressure is too low. It may be necessary to monitor fuel pressure while driving the vehicle at various road speeds and/or loads to confirm. Refer to Fuel System Diagnosis. Exhaust leaks. If there is an exhaust leak, the engine can cause outside air to be pulled into the exhaust and past the sensor. Vacuum or crankcase leaks can cause a lean condition and/or possibly a high idle. If the above are OK, it is a faulty HO2S. Never solder the HO2S wires.